Differential cellular and subcellular distribution of glutamate transporters in the cat retina

• Published in: Visual neuroscience 2004-07, Vol.21 (4), p.551-565
• Main Authors: FYK-KOLODZIEJ, BOZENA, QIN, PU, DZHAGARYAN, ARTURIK, POURCHO, ROBERTA G.
• Format: Article
• Language: English
• Subjects: Amacrine Cells - metabolism; Amino acids; Animals; Astrocytes - metabolism; Biological and medical sciences; Cats - metabolism; Cells; Diabetic retinopathy; Eye and associated structures. Visual pathways and centers. Vision; Fundamental and applied biological sciences. Psychology; Glutamate transporters; Glutamic Acid - metabolism; Immunohistochemistry - methods; Molecular weight; Monosaccharide Transport Proteins - metabolism; Retina - cytology; Retina - metabolism; Retinal Ganglion Cells - metabolism; Retinal neurons; Staining and Labeling; Studies; Subcellular Fractions - metabolism; Tissue Distribution; Vertebrates: nervous system and sense organs
• ISSN: 0952-5238; 1469-8714
• DOI: 10.1017/S0952523804214067

Retrieval of glutamate from extracellular sites in the retina involves at least five excitatory amino acid transporters. Immunocytochemical analysis of the cat retina indicates that each of these transporters exhibits a selective distribution which may reflect its specific function. The uptake of glutamate into Müller cells or astrocytes appears to depend upon GLAST and EAAT4, respectively. Staining for EAAT4 was also seen in the pigment epithelium. The remaining transporters are neuronal with GLT-1α localized to a number of cone bipolar, amacrine, and ganglion cells and GLT-1v in cone photoreceptors and several populations of bipolar cells. The EAAC1 transporter was found in horizontal, amacrine, and ganglion cells. Staining for EAAT5 was seen in the axon terminals of both rod and cone photoreceptors as well as in numerous amacrine and ganglion cells. Although some of the glutamate transporter molecules are positioned for presynaptic or postsynaptic uptake at glutamatergic synapses, others with localizations more distant from such contacts may serve in modulatory roles or provide protection against excitoxic or oxidative damage.